A simple low cost and highly efficient operation technique of three phase AC voltage controllers

Three phase AC voltage controllers ACVC have many industrial and residential applications. Thyristors and TRIACS play very important role in AC voltage controller ACVC. Synchronization of control signals with supply voltages is required for proper and balanced operation of power switches in ACVC. This paper presents a novel and low-cost synchronization and control signals generation for either thyristors or TRIACS in three phase AC voltage controllers. A single comparator and a single chip microcontroller are utilized for synchronization and real time operation of the power switches achieving smooth and fast control of the output voltage. The proposed technique avoids the problems of complex circuitries required in conventional operation of those power switches. Simulation and experimental validation of the proposed technique are presented. The three phase ACVC based on the proposed technique is applied as a soft starter of three phase induction motor.